<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        div {
            /* position: relative; */
            width: 0;
            height: 0;
            border-top: 9px solid transparent;
            border-right: 9px solid red;
            -webkit-transform: rotate(10deg);
            -moz-transform: rotate(10deg);
            -ms-transform: rotate(10deg);
            -o-transform: rotate(10deg);
        }

        div:after {
            content: "";
            position: absolute;
            border: 0 solid transparent;
            border-top: 3px solid red;
            border-radius: 20px 0 0 0;
            top: -12px;
            left: -9px;
            width: 12px;
            height: 12px;
            -webkit-transform: rotate(45deg);
            -moz-transform: rotate(45deg);
            -ms-transform: rotate(45deg);
            -o-transform: rotate(45deg);
        }
    </style>
</head>

<body>
    <div></div>
</body>

</html>